Machine lift or press mechanism



Sept. 5, 1967 w. JEWETT MACHINE LIFT OR PRESS MECHANISM 4 Sheets-Sheet 1 Filed March 30, 1966 /Nl ENTO/? WALTER L. JEWETT F l G l m m t w H P. m 1. A llllllll J r l l I I l|4ll| FHI IHHUHHHM n 1. ll 111 Hum WW id w I I l I I l I I l IL: ||l|| lllllriizillfi 1| illl ATTORNEY Sept. 5, 1967 w. JEWETT 3,339,482

MACHINE LIFT OR PRESS MECHANISM Filed March 30, 1966 4 Sheets-Sheet 2 F'IG.2

lNl/ENTOR WALTER L. JEWETT ,v N A7 TORNEY Sept. 5, 1967 w. L. JEWETT 3,339,482

MACHINE LIFT OR PRESS MECHANISM Filed March 50, 1966 4 Sheets-Sheet 3 m I 13A \N ATTORNEY United States Patent 3,339,482 MACHINE LIFT 0R PRESS MECHANISM Walter L. Jewett, Royal Oak, Mich., assignor to Allied Welder Corporation, Detroit, Mich., a corporation of Michigan Filed Mar. 30, 1966, Ser. No. 538,690 8 Claims. (Cl. 100-271) This invention relates to machine tool presses and in particular to novel mechanical actuating means developing compound harmonic motion producing greatly increased speed characteristics in intermediate travel positions of the platen and greatly reduced speed characteristics at end positions of travel of the platen with substantially constant speed drive application.

An object of the invention is to provide novel press actuating means which are simple in design and construction, inexpensive to manufacture, reliable in operation, and easy to engineer, adapt, and adjust for particular uses.

An object of the invention is to provide improved press actuating means for traveling platen presses which shortens the span of slow speed end travel and which lengthens the span of high speed intermediate travel and also increases the speed of the intermediate travel itself to save press operating time.

An object of the invention is to provide improved press actuating means having augmented acceleration and deceleration characteristics in the shortened slow speed spans adjacent the ends of travel to increase smoothness and to reduce shocks, and to provide increased strength, power, and control with increased mechanical advantage.

An object of the invention is to provide improved press actuating means which have increased strength, power, control, and mechanical advantage in the shortened low speed span so that acceleration and deceleration itself is augmented but without shock or vibration.

An object of the invention is to provide a press actuating mechanism wherein the primary drive is linear and is converted to rotary or angular motion by the mechanism so that the need for a rotary drive unit is eliminated.

An object of the invention is to provide a fail safe press actuating mechanism with the moving platen locked at the ends of travel in the up and down positions by the dead center condition of the cranks in conjunction with the crank locked in position by the cam, cam track in the torque arm, the lever, and the power cylinder.

An object of the invention is to produce a one hundred eighty degree crank angular motion with a ninety degree lever angular motion with the primary cylinder drive being linear to swing the lever.

An object of the invention is to provide a linear drive mechanism for a rotary crank with the mechanism moving the crank between dead center conditions without the mechanism itself assuming a dead center position.

An object of the invention is to provide a press which opens and closes faster than prior art presses so that it can maintain piece production at a high rate in keeping with other fast acting equipment on production lines.

These and other objects of the invention will become apparent by reference to the following description of a press embodying an example of the invention taken in connection with the accompanying drawings, in which:

FIG. 1 is an end elevational view of a press embodying the invention.

FIG. 2 is a side elevational view of the top portion of the press seen in FIG. 1.

FIG. 3 is an enlarged top plan view of the center portion of the press seen in FIGS. 1 and 2.

FIG. 4 is a cross-sectional view of FIG. 3 taken on the line 44 thereof or an enlarged cross-sectional view of -FIG. 2 taken on the line 44 thereof.

FIG. 5 is a collective schematic illustration of the actuating means at the top and bottom of sheet four of the drawings showing exemplary positions and relationships at various stages of the mechanism; and

FIG. 6 is a graphic illustration of the platen travel, crank linear travel, crank and arm angles of rotation, and lever angles of rotation at various stages of press operation.

Referring now to the drawings wherein like numerals refer to like and corresponding parts throughout the several views, the exemplary press and actuating means shown therein to illustrate the invention comprises a press 10 having a base 11, FIGS. 1 and 2. Four corner pillars 12 rise from the base 11. A top frame 13 rests on the pillars 12. Bearings 14 are mounted on the frame 13. A crankshaft 15 is rotatably mounted in the bearings 14. A crank 16 is attached to either end of the crankshaft 15. A slide 17 is bearinged on each crank 16. A horizontal channel member 18 houses the slide 17. Connecting rods 19 depend from the ends of each channel member 18. A platen 20 is attached to the bottom ends of the connecting rods 19 such as by cross-arms 21.

The platen 20 has a case 22. A well 23 guides the case 22. Bearing slides 24 on the pillars 12 cooperate with slide blocks 25 and 26 on the cross arms 21. The platen 20 is thus guided linearly in up and down movement.

The horizontal channel member 18 is attached to a vertical channel member 28 on the top frame 13. The horizontal channel member 18 is thus guided by the vertical channel member 28 linearly in up and down movement as the slide 17 reciprocates horizontally. A weight counterbalancing air cylinder 29 is mounted at either end of the top frame 13 adjacent the vertical slide 27. An arm 30 connects the air cylinder 29 with the vertical slide 27. Air pressure in the cylinder 29 is adjusted to counterbalance the dead weight of the platen 20, arms 21, connecting rods 19, channel members 18, and vertical slides 27. These parts are thus substantially floatingly suspended relative to the actuating means.

Referring now to FIGS. 24, a torque arm 31 is mounted on the crankshaft 15. The torque arm 31 lies normal to the crank 16. When the crank is at dead center vertical positions, the torque arm is horizontal. When the crank is in a mid-throw horizontal position, the torque arm 31 is vertical. Thus swinging the torque arm 31 from the horizontal position seen in FIG. 4 over the top to the press 10 to a like horizontal position on the other side, rotates the crankshaft 15 angularly This swings the crank 16 angularly 180 from its vertical down position to its vertical up position. This moves the platen 20 from its full down position to its full up position. The simple harmonic motion of the crank 16 provides inherent simple harmonic acceleration, deceleration, and speed characteristics in the actuating means so far described. Reverse swinging of the torque arm 31 rotates the crankshaft 14 and crank 16 angularly 180 and moves the platen 20 to its full down position. It will be understood therefore that if substantially constant speed drive is applied to the torque arm 31, that only simple harmonic motion, speed, acceleration, and deceleration results are obtained. This is altered in the invention by moving the torque arm 31 with accelerated and decelerated drive speed as follows.

A fulcrum shaft 32 lies in bearings 33 secured to the top frame 13. The fulcrum shaft 32 is positioned diametrically between the crankshaft 15 and the platen 20. A lever 34 is pivoted on the fulcrum shaft 32 and lies adjacent and extends past the torque arm 31. The torque arm 31 has a radial cam track 35. The lever 34 has a cam 36 lying in the cam track 35 of the torque arm 31. A bearing block 37 is mounted on the outer end of the lever 34. A pin 38 lies in the bearing block 37. A piston rod 39 connects to the pin 38. A cylinder 40 actuates the piston rod 39. The cylinder 40 is mounted on trunions 41 bearinged in a yoke 42 on the top frame 13.

In the drawings the cylinder 40, lever 34, cam 36, torque arm 31, and crank 16 are shown in the down position of the platen 20. This is the open position of the press 10 in the illustrated embodiment with the piston rod 39 retracted. The lever 34 lies a little more than 45 to the press vertical axis with the torque arm 31 horizontal and the crank 16 vertically down. From this open position, the cylinder extends the piston rod 39 to swing the lever 34 somewhat over 90 to a position a little over 45 to the press vertical axis on the opposite side of the press as shown by the broken line are of FIG. 4. This arc illustrates the path of the cam 36.

The arcuate path of the cam 36 relative to the fulcrum shaft 32 is elliptical relative to the crankshaft 15. The cam 36 moves eccentrically relative to the crankshaft 15 and the torque arm 31. Different radial spacing occurs between the cam 36 and the crankshaft 15. The differences in radial spacing causes the cam to slide radially of the crankshaft 15 in the cam track 35 of the torque arm 31. The cam 36 is at maximum radial distance from the crankshaft 15 at the ends of pivotal movement of the lever 34 and at minimum radial distance from the crankshaft 15 intermediate the ends of pivotal movement of the lever 34. The cam 36 itself is at zero angle of inclined plane relative to the torque arm 31 intermediate the ends of pivotal movement of the lever 34 with no camming mechancial advantage. The greater the camming angle, the less angular movement is imparted to the torque arm 31. The lesser the camming angle the more angular movement is imparted to the torque arm 31. This is concurrent with the radial distance mechanical advantage of the point of engagement between the cam 36 and torque arm 34 relative to the crankshaft 15. In other words, the radial distance mechanical advantage and the cam mechanical advantage increase and decrease together additively with speed of angular movement of the torque arm 31 being inversely proportional to the additive mechanical advantages. This is cumulated additively with the motion of the crank 16 relative to the platen 20 as the ends of crank 16 throw adjacent dead center are at the ends of pivotal movement of the lever 34. Also the crank 16 throw intermediate its dead center position is at maximum linear speed when the torque arm 31 is its intermediate position of maximum speed.

It is to be noted that with constant speed linear movement of the piston rod some of its linear movement is converted to non-linear movement in the swing of the lever in an arc so that the angular speed of the lever is a little slower than the piston rod speed adjacent its ends of movement and as fast as the piston rod speed at the mid point.

These features of operation are schematically shown in FIG. 4 and graphically in FIG. 6 and to which reference is now made.

FIG. position A shows the lever 34 at one end of pivotal movement at about 45 to the press vertical axis, the torque arm 31 horizontal, the crank 16 vertical on dead center, and the cam 36 at maximum radial distance leverage and maximum camming angle relative to the torque arm 31. FIG. 5 position A corresponds to position A. of FIG. 6.

FIG. 5 position B shows the lever 34 at an angular position 15 from A with the torque arm 31 and crank 16 at an angular position about 11 from A and the crank 16 moved about 1.6% of its linear throw. FIG. 5 position B corresponds to position B of FIG. 6. Here these angular motions produce about 1.6% of total platen 20 travel or 1.6 of a 100" travel or .4" of a 25" travel. Thus with about one sixth of lever 34 angular movement, the platen only travels about 1.6% of its total linear movement at either end of its travel. This of course is average movement for the selected lever sector and it is therefore obvious that the linear movement of the platen relative to lever angular movement moves from and to a standing position with extremely gradual compound harmonic motion with the majority of platen linear travel between A and B occurring adjacent B. Thus the platen is actuated with extremely gradual acceleration and deceleration adjacent its ends of travel. 7

FIG. 5 position C shows the lever 34 at an angular position 15 from B and 30 from A with the torque arm 31 and crank 16 moved about 16% of its linear throw to C from B and about 17.6% of its linear throw from A. FIG. 5 position C corresponds to intermediate position C of FIG. 6. Here these angular motions from B to C produce about 16% of total platen 20 travel or 16" of a 100 travel or 4" of a 25" travel. Thus with about one sixth of lever movement, the platen here travels about 16% of its total linear movement. This of course is also an average movement for the selected lever sector and it is therefore obvious that the platen is accelerating or decelerating at this position with faster motion adjacent C position and slower motion adjacent B josition. Thus the platen is gradually but rapidly accelerated and decelerated in the intermediate sectors of lever movement.

FIG. 5 position D shows the lever 34 at an angular position 15 from C, 30 from B, and 45 from A with the torque arm 31 and crank 16 at an angular position about 40 from C, 79 from B, and from A and the crank 16 moved about 32.4% of its linear throw from C, 48.4% of its linear throw from B, and 50% of its linear throw from A. FIG. 5 position D corresponds to center position D of FIG. 6. These angular motions from C to D produce about 32.4% of total platen 20 travel or 32.4" of a travel or 8.1" of a 25" travel. Thus with about one sixth of lever angular movement, the platen here travels about 32.4% of its total linear movement adjacent and at its mid-point of travel. This also is an average movement for the selected lever sector and its is therefore obvious that the platen is accelerating or decelerating relative to the D position at which it obtains its maximum speed. Thus the platen 20 is accelerated and decelerated to and from position D in the stated center sectors of lever movement with the crank 16 in the middle of its throw.

FIG. 5 positions C, B, and A, respectively correspond to FIG. 5 positions C, B, and A. The foregoing description of positions C, B, and A applies equally to positions C, B, and A. This is graphically shown in FIG. 6.

It will now be understood that the platen 20 reciprocates up and down linearly on a vertical axis and that the crank 16 swings back and forth in an arc. The torque art 31 also swings back and forth 180 in an arc. The torque arm 31 lies normal to the crank 16 at all times. The lever 34 swings back and forth 90 in an arc. The direction of platen 20 movement is therefore dependant on the direction of lever 34 movement.

The crank 16 throws between vertically up and down positions of dead center. The speed of the simple harmonic motion relationship between the crank 16 and the platen 20 is slowed down adjacent the crank 16 dead center positions and increased to and decreased from the crank 16 mid-throw position. This is accomplished by the eccentric relationship of the cam 36 relative to the torque arm 31 with the torque arm 31 moving slower than the lever 34 adjacent the ends of movement and faster than the lever 34 intermediate the ends of movement.

It can now be seen that the lever 34 has a constant speed movement and that the platen 20 has a varied speed movement of compound harmonic motion of increased acceleration intermediate the ends of travel and decreased deceleration characteristics adjacent the ends of travel.

Although but a single embodiment of the invention has been shown and described in detail, it is obvious that many changes may be made in the size, shape, length, spacing, and other details and arrangements of the various elements of the invention within the scope of the appended claims.

I claim:

1. Operating linkage for a press having a platen moved in a stroke between open and closed positions,

a crank connected to said platen,

a crankshaft having an axis rotatably supporting said crank,

a torque arm on said crankshaft,

a cam track in said torque arm radially of said crankshaft,

a cam roler in said cam track,

a fulcrum shaft lying radially of said crankshaft; and

an actuating lever pivoted on said fulcrum shaft adapted to swing through the axis of said crankshaft from one side of said crankshaft to the other side of said crankshaft; said cam roller being mounted on said lever at a position spaced from said fulcrum shaft so as to lie and swing in an are beyond the axis of said crankshaft;

said lever swinging said c-am roller through a relatively small angle on a relatively long radius relative to said fulcrum shaft; said cam ro'ller swinging said torque arm through a relatively large angle on relatively short varied radii relative to said crankshaft with said varied radii being of maximum length at the ends of movement and minimum length intermediate the ends of movement;

said cam roller engaging said arm through said cam track at varied camming angles with the varied camming angles being maximum at the ends of travel and minimum intermediate the ends of travel,

whereby, harmonic motion is transferred to said crank by said linkage from constant lever motion to accelerate and decelerate the speed of motion of said crank adjacent the ends of travel and to increase the speed of travel of said crank intermediate the ends of travel.

2. In a device as set forth in claim 1,

said operating linkage locating said crank at a one position of dead center on one side of said crankshaft at one end of travel of said linkage and moving said crank to the other position of dead center on the other side of said crankshaft at the other end of travel of said linkage;

said crank moving between said dead center positions with inherent harmonic motion;

The harmonic motion of said crank being thereby compounded with the harmonic motion of said linkage to increase acceleration and deceleration adjacent the ends of the stroke of the platen and to increase speed of platen stroke intermediate the ends of the platen stroke.

3. In a device as set forth in claim 1, said lever having an end extending radially outwardly a greater distance than said cam roller, and

a power cylinder connected to said lever end for operating said lever with mechanical advantage relative to said cam roller.

4. In a device as set forth in claim 1, a connecting rod connecting said crank and platen a slide way on said connecting rod,

a slide in said slideway;

said crank being connected to said slide; and

guide means channeling said connecting rod for linear reciprocating movement; said connecting rod, slideway, and slide thereby transferring harmonic motion to a platen undisturbed by angular movement of said connecting rod and to insure linear reciprocation of a platen to which said connecting rod is connected.

5. A press comprising a frame,

a crankshaft on said frame,

a crank on said crankshaft,

a platen in said frame reciprocating on a linear axis,

.a connecting rod between said crank and said platen;

said crank having opposite dead center positions when lying parallel to said linear axis defining the open and closed positions of said platen;

a torque arm on said crankshaft normal to said crank;

in the open position of said platen said crank lying parallel to said linear axis and said torque arm lying normal to said linear axis;

a fulcrum shaft on said frame diametrically between said crankshaft and platen,

a lever pivoted on said fulcrum shaft at a mid-angle relative to said linear axis (such as 45) on one side of said linear axis in the open position of said platen;

said lever extending outwardly past the axial plane of said crankshaft; said lever lying adjacent said torque arm;

said torque arm having a radially outer end and a radial cam track;

in the open position of said platen said lever crossing said torque arm adjacent its outer end;

a cam on said lever on a relatively long radius from said fulcrum shaft lying in said torque arm cam track adjacent said torque arm outer end in the open position of said platen;

said lever having a radially outer end; and

a power cylinder on said frame connected to said lever outer end;

said cylinder pivoting said lever from said stated midangle position on one side of said press linear axis, through a position parallel to said linear axis, to a mid-angle position on the other side of said linear ax1s,

said lever swinging said cam in a path arcuate relative to said fulcrum shaft;

said cam path describing an elipse relative to said crankshaft;

said cam path elipse being eccentric relative to said torque arm;

the axial spacing of said crankshaft and said fulcrum shaft and the length of said cam radius being such that said cam path elipse extends 180 angularly of said crankshaft;

pivotal movement of said lever from the open position of said platen sliding said cam in said cam track and swinging said torque arm with maximum cam advantage and torque arm leverage and minimum angular movement adjacent the dead center position of said crank so that compound harmonic motion gradually accelerates platen speed of movement from the open position and gradually decelerates platen speed of movement toward the closed position,

said lever in its first 45 of angular movement moving said cam through of angular movement relative to said crankshaft and said crank 90 to move said platen to a travel position midway between its open and closed positions with said torque arm lying parallel to said linear axis and said crank lying, normal to said linear axis and with said arm being at a flat cam angle relative to said cam and said crank being at maximum throw so that said compound harmonic motion is at maximum speed of movement at the mid-travel position of said platen.

6. A fast acting mechanical press having a platen actuated by compound harmonic motion means to provide increased acceleration and decreased deceleration characteristics at ends of travel and increasing speed of intermediate travel to save press opening and closing time, comprising, a platen mounted in said press movable between open and closed positions, a crankshaft rotatably mounted on said press, a crank on a said crankshaft connected to said platen; said crank in an arc of harmonically moving said platen between open and closed positions at the opposite dead center position of said crank;

a torque arm on said crankshaft lying normal to said crank having a cam track lying radially of said crankshaft,

fulcrum shaft on said frame lying diametrically between said crankshaft and said platen,

a drive lever having one end pivoted on said fulcrum shaft and an outer end extending outwardly beyond said crank-shaft; said lever being adapted to swing in an are through the axis of said crankshaft,

a cam on said lever radially spaced from said fulcrum shaft on a relatively long radius so as to lie beyond said crankshaft;

said cam lying in said torque arm cam track; and

a power cylinder connected to said lever;

said lever being swung by said power cylinder through a relatively small angle such as 90 to swing said cam in an are on a long radius relative to said crankshaft from one side of said crankshaft to the other side of said crankshaft over the axis of said crankshaft in an elipse so that said cam moves eccentrically relative to said torque arm;

said cam thereby swinging said torque arm, crankshaft and crank in a relatively large angle such as 180,

said actuating means being so combined that the positions of greatest mechanical advantage and least speed of all elements are additively integrated at the ends of platen travel and so that the positions of least mechanical advantage and most speed of all elements are additively integrated intermediate the ends of platen travel.

7. A fast acting press, comprising,

a moving platen in said press having an axis of travel,

a crankshaft on said press in the axis of travel of said platen,

a crank on said crankshaft;

said crank being connected to said platen;

180 rotation of said crankshaft and crank moving said platen in its axis of travel between open and closed positions in said press corresponding to opposite dead center positions of said crank relative to said crankshaft and said platen,

a torque arm on said crankshaft normal to said crank so as to lie normal to said platen travel axis at the open and closed positions of said platen and to lie parallel to axis of travel of said platen intermediate said open and closed positions of said platen,

a radial cam track in said torque arm,

a cam in said cam track,

a fulcrum shaft on said frame lying in the axis of travel of said platen between said crankshaft and said platen,

a lever having an inner end pivoted on said fulcrum shaft and an outer end extending outwardly beyond said crankshaft,

said cam being carried by said lever on a relatively long radius relative to said fulcrum shaft locating said cam outwardly of said crankshaft relative to said platen, and

a power cylinder connected to said lever outer end;

said power cylinder swinging said lever to move said cam through a relatively small angle such as 90 to swing said cam on said relatively long radius relative to said crankshaft in a relatively long are over said crankshaft in an elipse from one side of said crankshaft to the other side of said crankshaft, thereby eccentrically swinging said torque arm through a 180 angle rotating said crankshaft and crank 180 moving said platen between open and closed positions.

8. A press having an increased span of fast travel with increased speed in the increased span, comprising a reciprocating platen in said press traveling on a linear axis, 7

a fulcrum shaft on said press having a pivot axis transverse to and axially of said linear axis,

a lever having an inner end pivoted on said fulcrum shaft and an outer end extending outwardly relative to said platen,

said lever having a center position paralleling said linear axis in extension,

said lever being bi-directionally swin-gable from said center position to opposite side positions at a relatively small angle relative to said linear axis in extension such as 45; said lever thereby having a cumulative angular movement from side to side such as a power cylinder on said frame connected to said lever outer end,

a cam on said lever radially spaced from said fulcrum shaft on a relatively long radius; said lever swing said cam in a relatively long arc bisected by said press linear axis in extenison;

a crankshaft on said frame lying parallel to said fulcrum shaft and outwardly beyond said fulcrum shaft relative to said platen and axially of said press linear ax1s,

said fulcrum shaft and said crankshaft thereby having axis of rotation axially of said press linear axis and aligned relative thereto;

said cam arc of said lever describing an elipse relative to said crankshaft axis so as to move eccentrically relative thereto,

the axial spacing of said crankshaft and said fulcrum shaft and the length of said cam radius being such that said cam elipse extends 180 angularly of said crankshaft axis;

a torque arm on said crankshaft having a radial cam track engaging said cam on said lever;

said cam at a side position of said lever engaging said torque arm remote from said crankshaft at a relative small cam angle producing maximum cam mechanical advantage and minimum motion together with maximum leverage on said torque arm; said cam at the center position of said lever engaging said torque arm proximate to said crankshaft at a perpendicular cam angle producing minimum cam mechanical advantage and maximum motion together with minimum leverage on said torque arm,

said lever cam thereby initially moving said crankshaft through said torque arm from a lever side position toward a lever center position with maximum force and minimum speed and gradually subsequently moving said crankshaft with diminishing force and increasing speed to the center position of said lever, and gradually subsequently moving said crankshaft with increasing force and diminishing speed to the opposite side position of said lever at which minimum speed and maximum force obtains;

a crank on said crankshaft normal to torque arm connected to said platen;

said crank thereby being at dead center relative to said crankshaft and said platen at the ends of lever movement so that the harmonic motion of said crank is additive and cumulative to said crankshaft harmonic motion.

References Cited UNITED STATES PATENTS 336,305 2/1886 Ertel 283 XR 2,951,379 9/ 1960 Longfield 1002l4 XR 3,000,295 9/ 1961 Fenton 100214 3,140,654- 7/1964 Jewett 100-272 XR 3,157,113 11/1964 Jewett 100--282 XR BILLY I. WILHITE, Primary Examiner. 

5. A PRESS COMPRISING A FRAME, A CRANKSHAFT ON SAID FRAME, A CRANK ON SAID CRANKSHAFT, A PLATEN IN SAID FRAME RECIPROCATING ON A LINEAR AXIS, A CONNECTING ROD BETWEEN SAID CRANK AND SAID PLATEN; SAID CRANK HAVING OPPOSITE DEAD CENTER POSITIONS WHEN LYING PARALLEL TO SAID LINEAR AXIS DEFINING THE OPEN AND CLOSED POSITIONS OF SAID PLATEN; A TORQUE ARM ON SAID CRANKSHAFT NORMAL TO SAID CRANK; IN THE OPEN POSITION OF SAID PLATEN SAID CRANK LYING PARALLEL TO SAID LINEAR AXIS AND SAID TORQUE ARM LYING NORMAL TO SAID LINEAR AXIS; A FULCRUM SHAFT ON SAID FRAME DIAMETRICALLY BETWEEN SAID CRANKSHAFT AND PLATEN, A LEVER PIVOTED ON SAID FULCRUM SHAFT AND A MID-ANGLE RELATIVE TO SAID LINEAR AXIS (SUCH AS 45*) ON ONE SIDE OF SAID LINEAR AXIS IN THE OPEN POSITION OF SAID PLATEN; SAID LEVER EXTENDING OUTWARDLY PAST THE AXIAL PLANE OF SAID CRANKSHAFT; SAID LEVER LYING ADJACENT SAID TORQUE ARM; SAID TORQUE ARM HAVING A RADIALLY OUTER END AND A RADIAL CAM TRACK; IN THE OPEN POSITION OF SAID PLATEN SAID LEVER CROSSING SAID TORQUE ARM ADJACENT ITS OUTER END; A CAM ON SAID LEVER ON A RELATIVELY LONG RADIUS FROM SAID FULCRUM SHAFT LYING IN SAID TORQUE ARM CAM TRACK ADJACENT SAID TORQUE ARM OUTER END IN THE OPEN POSITION OF SAID PLATEN; SAID LEVER HAVING A RADIALLY OUTER END; AND A POWER CYLINDER ON SAID FRAME CONNECTED TO SAID LEVER OUTER END; 